Research On The Controllable Synthesis,Stability And Optical Properties Of Lead Halide Perovskite Quantum Dots

Efficient use of solar energy is currently one of the best solutions to balance energy and environmental problems.Current photoelectric conversion devices generally have problems such as expensive materials and complex processes.Because of these excellent photoelectric properties and low processing cost,perovskite materials have been vigorously explored by scientific researchers all over the world.In just ten years,perovskite solar cells have achieved a photoelectric conversion efficiency of 25.5%,and perovskite quantum dots combine the excellent photoelectric properties of perovskite materials with the properties of traditional semiconductor quantum dots,such as higher fluorescence quantum yields,PLQY,extremely narrow half-value width,adjustable band gap,full-spectrum coverage in visible light,etc.These have made perovskite quantum dots one of the most promising optoelectronic materials at present,and perovskite quantum dots are widely used in light-emitting diodes and solar cells,Lasers,photodetectors,etc.However,the current research on perovskite quantum dots is mainly focused on all-inorganic materials.In addition,the development of perovskite materials is severely restricted by poor stability.Therefore,this article mainly focuses on the synthesis of perovskite quantum dots and the improvement of perovskite quantum dots.Our research lays the foundation for the practical application of perovskite in the future.The main work of this paper is as follows:(1)In this chapter,we have improved the synthesis method of traditional classical perovskite quantum dots from the perspectives of raw materials,surface ligands,and reaction solvents.The morphology of CsPbBr3 nanodisks is adjusted through post-synthesis processing methods,and uniform FAPbI3 nanorods are synthesized using n-octane as the reaction solvent,which further promotes the basic research of perovskite quantum dots.(2)In this chapter,we used the method of ligand exchange after synthesis to prepare CsPbBr3 quantum dots with X-type ligands(C10H5F17S).With the stability of the Pb-S chemical bond and the force between the ligand molecules,small C10H5F17S molecules can be coordinated to the surface of the quantum dots.The introduction of the fluorine molecular layer on the surface of the quantum dots can effectively enhance the water stability of the material in our method,the small molecule ligand exchange can balance the conductivity and stability of the material.In addition,the quantum dots treated by this method still maintain good colloidal properties,and the solution process reduces the subsequent processing costs Our proposed synthetic post-processing The method will promote the application of CsPbBr3 quantum dots in optoelectronic devices(3)We propose a simple and effective method to inhibit the halogen ion exchange reaction of FA-based quantum dots,while enhancing the stability of the material to water.The colloidal quantum dots are neatly embedded in the PbSO4 shell with the aid of PbSO4-oleate molecular clusters.This self-assembly process forms a PbSO4 layer on the superlattice surface of the quantum dots.In the shell,this self-assembly process forms a PbSO4 layer on the superlattice surface of the quantum dot.These halogen-free thin shells can act as a barrier to effectively prevent the ion migration process and the destruction of the perovskite structure by water molecules.It is beneficial to the application of mixed halogen perovskite quantum dots in optical devices.